Quantitative imaging of elastic, piezoelectric and frictional properties of material surfaces using atomic force acoustic microscopy

In Atomic Force Microscopy the deflection and torsion of micro-fabricated elastic beams with a sensor tip are used to generate high-resolution images of sample surfaces. In dynamic modes, the cantilever is vibrated while the surface is scanned. Between the tip and the sample the force interaction occurs at least during a fraction of a vibration cycle. In Atomic Force Acoustic Microscopy flexural and torsional cantilever vibrations are excited by out-of-plane and in-plane ultrasonic sample surface vibrations, respectively. The contrast of AFAM images contains local elastic, adhesive and frictional sample properties. In the piezo-mode, an electric ac-voltage applied at the sensor tip contacting excites local surface vibrations and hence probes the local piezoelectric activity. Quantitative evaluations of AFAM images in the linear elastic interaction region yield local indention and shear moduli of sample surfaces.